In a front section of a vehicle body are provided left and right front side frames, left and right sills and a central tunnel section that are among principal components of the vehicle body. At the time of occurrence of a so-called frontal collision, where collision force acts on the front surface of the vehicle, the collision force transmits via the left and right front side frames to the left and right sills and the central tunnel section and then disperse to a rear section of the vehicle body. Technique related to the left and right front side frames are known from Patent Literature 1 and Patent Literature 2.
In the vehicle body disclosed in Patent Literature 1, a vehicle-traveling power unit (comprising an engine and a transmission) is disposed between front half portions of the left and right front side frames, and left and right front wheels are disposed laterally outward, in a vehicle width direction, of rear portions of the left and right front side frames. Particularly, if an engine room having a space short in a front-rear direction the vehicle body is employed in the vehicle body, the vehicle-traveling power unit is mounted in the engine room in such a manner as to be elongated in the vehicle width direction. In such a case, for example, a so-called transverse-mounted engine having a crankshaft oriented in the vehicle width direction is employed as the engine. Further, in the vehicle body disclosed in Patent Literature 1, rear half portions of the left and right front side frames are curved inwardly in such a manner as to gradually approach each other in a direction toward the rear of the vehicle body, in order to widen steerable ranges of the left and right front wheels. Thus, the curved rear half portions of the left and right front side frames can have an increased strength.
Further, the vehicle body disclosed in Patent Literature 2 is constructed to suppress occurrence of rapid bending of the left and right front side frames against collision force acting from the front of the vehicle body.
In recent years, there has been an increasing demand for a technique for efficiently dispersing collision force from the front of the vehicle body throughout the entire vehicle body.